diff --git a/runtime/syntax/generator/gen_syntax_vim.vim b/runtime/syntax/generator/gen_syntax_vim.vim
index 5c797de..b4feeed 100644
--- a/runtime/syntax/generator/gen_syntax_vim.vim
+++ b/runtime/syntax/generator/gen_syntax_vim.vim
@@ -279,6 +279,7 @@
 	\	'autocmd', 'augroup', 'doautocmd', 'doautoall',
 	\	'echo', 'echoconsole', 'echoerr', 'echohl', 'echomsg', 'echon', 'echowindow',
 	\	'execute',
+	\ 'function', 'endfunction', 'def', 'enddef',
 	\	'behave', 'augroup', 'normal', 'syntax',
 	\	'append', 'insert',
 	\	'Next', 'Print', 'X',
diff --git a/runtime/syntax/generator/vim.vim.base b/runtime/syntax/generator/vim.vim.base
index 46285f3..0004109 100644
--- a/runtime/syntax/generator/vim.vim.base
+++ b/runtime/syntax/generator/vim.vim.base
@@ -167,7 +167,7 @@
 syn case match
 
 " All vimCommands are contained by vimIsCommand. {{{2
-syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutoCmd,vimAugroup,vimBehave,@vimEcho,vimExecute,vimIsCommand,vimExtCmd,vimFunction,vimGlobal,vimHighlight,vimLet,vimMap,vimMark,vimNotFunc,vimNorm,vimSet,vimSyntax,vimUnlet,vimUnmap,vimUserCmd,vimMenu,vimMenutranslate
+syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutoCmd,vimAugroup,vimBehave,vimDef,@vimEcho,vimEnddef,vimEndfunction,vimExecute,vimIsCommand,vimExtCmd,vimFor,vimFunction,vimGlobal,vimHighlight,vimLet,vimMap,vimMark,vimNotFunc,vimNorm,vimSet,vimSyntax,vimUnlet,vimUnmap,vimUserCmd,vimMenu,vimMenutranslate
 syn match vimCmdSep	"[:|]\+"	skipwhite nextgroup=@vimCmdList,vimSubst1
 syn match vimIsCommand	"\<\%(\h\w*\|[23]mat\%[ch]\)\>"	contains=vimCommand
 syn match vimVar	      contained	"\<\h[a-zA-Z0-9#_]*\>"
@@ -227,7 +227,7 @@
 
 " Operators: {{{2
 " =========
-syn cluster	vimOperGroup	contains=vimEnvvar,vimFunc,vimFuncVar,vimOper,vimOperParen,vimNumber,vimString,vimType,vimRegister,@vimContinue,vim9Comment,vimVar
+syn cluster	vimOperGroup	contains=vimEnvvar,vimFunc,vimFuncVar,vimOper,vimOperParen,vimNumber,vimString,vimRegister,@vimContinue,vim9Comment,vimVar
 syn match	vimOper	"||\|&&\|[-+*/%.!]"				skipwhite nextgroup=vimString,vimSpecFile
 syn match	vimOper	"\%#=1\(==\|!=\|>=\|<=\|=\~\|!\~\|>\|<\|=\|!\~#\)[?#]\{0,2}"	skipwhite nextgroup=vimString,vimSpecFile
 syn match	vimOper	"\(\<is\|\<isnot\)[?#]\{0,2}\>"			skipwhite nextgroup=vimString,vimSpecFile
@@ -239,28 +239,67 @@
 
 " Functions : Tag is provided for those who wish to highlight tagged functions {{{2
 " =========
-syn cluster	vimFuncList	contains=vimCommand,vimFunctionError,vimFuncKey,Tag,vimFuncSID
-syn cluster	vimFuncBodyList	contains=@vimCmdList,vimCmplxRepeat,vimComment,vim9Comment,vimContinue,vimCtrlChar,vimEnvvar,vimFBVar,vimFunc,vimFunction,vimFuncVar,vimLetHereDoc,vimLineComment,vimNotation,vimNotFunc,vimNumber,vimOper,vimOperParen,vimRegion,vimRegister,vimSearch,vimSpecFile,vimString,vimSubst
-syn match	vimFunction	"\<\(fu\%[nction]\)!\=\s\+\%(<[sS][iI][dD]>\|[sSgGbBwWtTlL]:\)\=\%(\i\|[#.]\|{.\{-1,}}\)*\ze\s*("	contains=@vimFuncList nextgroup=vimFuncBody
-syn match	vimFunction	"\<def\s\+new\i\{-}(" contains=@vimFuncList nextgroup=vimFuncBody
-syn match	vimFunction	"\<def!\=\s\+\%(\i\|[#.]\|{.\{-1,}}\)*\ze\s*(" contains=@vimFuncList nextgroup=vimFuncBody
-"syn match	vimFunction	"\<def!\=\ze\s*(" contains=@vimFuncList nextgroup=vimFuncBody
+syn cluster	vimFuncList	contains=vimFuncBang,vimFunctionError,vimFuncKey,vimFuncSID,Tag
+syn cluster	vimDefList	contains=vimFuncBang,vimFunctionError,vimDefKey,vimFuncSID,Tag
+syn cluster	vimFuncBodyList	contains=@vimCmdList,vimCmplxRepeat,vimComment,vimContinue,vimCtrlChar,vimDef,vimEnvvar,vimFBVar,vimFunc,vimFunction,vimFuncVar,vimLetHereDoc,vimLineComment,vimNotation,vimNotFunc,vimNumber,vimOper,vimOperParen,vimRegion,vimRegister,vimSearch,vimSpecFile,vimString,vimSubst
+syn cluster	vimDefBodyList	contains=@vimCmdList,vimCmplxRepeat,vim9Comment,vimContinue,vimCtrlChar,vimDef,vimEnvvar,vimFBVar,vimFunc,vimFunction,vimLetHereDoc,vim9LineComment,vimNotation,vimNotFunc,vimNumber,vimOper,vimOperParen,vimRegion,vimRegister,vimSearch,vimSpecFile,vimString,vimSubst
+
+syn region	vimFuncPattern	contained		matchgroup=vimOper start="/" end="$" contains=@vimSubstList
+syn match	vimFunction	"\<fu\%[nction]\>"	skipwhite nextgroup=vimCmdSep,vimComment,vimFuncPattern contains=vimFuncKey
+syn match	vimDef	"\<def\>"		skipwhite nextgroup=vimCmdSep,vimComment,vimFuncPattern contains=vimDefKey
+
+syn match	vimFunction	"\<fu\%[nction]\>!\=\s*\%(<[sS][iI][dD]>\|[sg]:\)\=\%(\i\|[#.]\|{.\{-1,}}\)\+"	contains=@vimFuncList skipwhite nextgroup=vimFuncParams
+syn match	vimDef	"\<def\s\+new\%(\i\|{.\{-1,}}\)\+"				contains=@vimDefList            nextgroup=vimDefParams
+syn match	vimDef	"\<def\>!\=\s*\%(<[sS][iI][dD]>\|[sg]:\)\=\%(\i\|[#.]\|{.\{-1,}}\)\+"		contains=@vimDefList            nextgroup=vimDefParams
+
+syn match	vimFuncComment	contained	+".*+ skipwhite skipnl nextgroup=vimFuncBody,vimEndfunction
+syn match	vimDefComment	contained	"#.*" skipwhite skipnl nextgroup=vimDefBody,vimEnddef
+
+syn match	vimFuncBang	contained	"!"
+syn match	vimFuncSID	contained	"\c<sid>"
+syn match	vimFuncSID	contained	"\<[sg]:"
+syn keyword	vimFuncKey	contained	fu[nction]
+syn keyword	vimDefKey	contained	def
+
+syn region	vimFuncParams	contained	matchgroup=Delimiter start="(" skip=+\n\s*\\\|\n\s*"\\ + end=")" skipwhite skipnl nextgroup=vimFuncBody,vimFuncComment,vimEndfunction,vimFuncMod contains=vimFuncParam,@vimContinue
+syn region	vimDefParams	contained	matchgroup=Delimiter start="("		   end=")" skipwhite skipnl nextgroup=vimDefBody,vimDefComment,vimEnddef,vimReturnType	 contains=vimDefParam,vim9Comment
+syn match	vimFuncParam	contained	"\<\h\w*\>\|\.\.\."	skipwhite nextgroup=vimFuncParamEquals
+syn match	vimDefParam	contained	"\<\h\w*\>"		skipwhite nextgroup=vimParamType,vimFuncParamEquals
+
+syn match	vimFuncParamEquals contained	"="			skipwhite        nextgroup=@vimExprList
+syn match	vimFuncMod	 contained	"\<\%(abort\|closure\|dict\|range\)\>"	skipwhite skipnl nextgroup=vimFuncBody,vimFuncComment,vimEndfunction,vimFuncMod
+
+syn region	vimFuncBody	contained	start="^"	matchgroup=vimCommand end="\<endfu\%[nction]\>"	contains=@vimFuncBodyList
+syn region	vimDefBody	contained	start="^"	matchgroup=vimCommand end="\<enddef\>"	contains=@vimDefBodyList
+
+syn match	vimEndfunction	"\<endf\%[unction]\>"
+syn match	vimEnddef	"\<enddef\>"
 
 if exists("g:vimsyn_folding") && g:vimsyn_folding =~# 'f'
- syn region	vimFuncBody  contained	fold start="\ze\s*("	matchgroup=vimCommand end="\<\(endf\>\|endfu\%[nction]\>\|enddef\>\)"		contains=@vimFuncBodyList
-else
- syn region	vimFuncBody  contained	start="\ze\s*("		matchgroup=vimCommand end="\<\(endf\>\|endfu\%[nction]\>\|enddef\>\)"		contains=@vimFuncBodyList
+ syn region	vimFuncFold	start="\<fu\%[nction]\>!\=\s*\%(<[sS][iI][dD]>\|[sg]:\)\=\%(\i\|[#.]\|{.\{-1,}}\)\+\s*("	end="\<endf\%[unction]\>" contains=vimFunction fold keepend transparent
+ syn region	vimFuncFold	start="\<def\>!\=\s*\%(<[sS][iI][dD]>\|[sg]:\)\=\%(\i\|[#.]\|{.\{-1,}}\)\+("	end="\<enddef\>"	        contains=vimDef      fold keepend transparent
+ syn region	vimFuncFold	start="\<def\s\+new\%(\i\|{.\{-1,}}\)\+("			end="\<enddef\>"	        contains=vimDef      fold keepend transparent
 endif
-syn match	vimFuncVar   contained	"a:\(\K\k*\|\d\+\)"
-syn match	vimFuncSID   contained	"\c<sid>\|\<s:"
-syn keyword	vimFuncKey   contained	fu[nction]
-syn keyword	vimFuncKey   contained	def
+
+syn match	vimFuncVar   contained	"a:\%(\K\k*\|\d\+\)\>"
 syn match	vimFuncBlank contained	"\s\+"
 
 syn keyword	vimPattern   contained	start	skip	end
 
+" Types: {{{2
+" =====
 " vimTypes : new for vim9
-syn match	vimType	":\s*\zs\<\(bool\|number\|float\|string\|blob\|list<\|dict<\|job\|channel\|func\)\>"
+syn region	vimReturnType	contained	start=":\s" end="$" matchgroup=vim9Comment end="\ze#" skipwhite skipnl nextgroup=vimDefBody,vimDefComment,vimEnddef contains=vimTypeSep transparent
+syn match	vimParamType	contained	":\s\+\a"			skipwhite skipnl nextgroup=vimFuncParamEquals   	        contains=vimTypeSep,@vimType
+
+syn match	vimTypeSep	contained	":\s\@=" skipwhite nextgroup=@vimType
+syn keyword	vimType	contained	any blob bool channel float job number string void
+syn match	vimType	contained	"\<func\>"
+syn region	vimCompoundType	contained	matchgroup=vimType start="\<func("            end=")" nextgroup=vimTypeSep contains=@vimType oneline transparent
+syn region	vimCompoundType   contained         matchgroup=vimType start="\<\%(list\|dict\)<" end=">"                      contains=@vimType oneline transparent
+syn match	vimUserType	contained	"\<\u\w*\>"
+
+syn cluster vimType contains=vimType,vimCompoundType,vimUserType
 
 " Keymaps: (Vim Project Addition) {{{2
 " =======
@@ -468,7 +507,7 @@
 syn keyword	vimEchohlNone	contained none
 syn case match
 
-syn cluster	vimEcho	contains=vimEcho.*
+syn cluster	vimEcho	contains=vimEcho,vimEchohl
 
 syn region	vimExecute	matchgroup=vimCommand start="\<exe\%[cute]\>" skip=+\\|\|\n\s*\\\|\n\s*"\\ + matchgroup=vimCmdSep end="|" excludenl end="$" contains=@vimContinue,@vimExprList transparent
 
@@ -552,7 +591,7 @@
 " ====================
 if !exists("g:vimsyn_noerror") && !exists("g:vimsyn_novimfunctionerror")
  " TODO: The new-prefix exception should only apply to constructor definitions.
- syn match	vimFunctionError	"\s\zs\%(new\)\@![a-z0-9]\i\{-}\ze\s*("			contained contains=vimFuncKey,vimFuncBlank
+ syn match	vimFunctionError	"\s\zs\%(new\)\@![a-z0-9]\i\{-}\ze\s*("		contained contains=vimFuncKey,vimFuncBlank
  syn match	vimFunctionError	"\s\zs\%(<[sS][iI][dD]>\|[sSgGbBwWtTlL]:\)\d\i\{-}\ze\s*("	contained contains=vimFuncKey,vimFuncBlank
  syn match	vimElseIfErr	"\<else\s\+if\>"
  syn match	vimBufnrWarn	/\<bufnr\s*(\s*["']\.['"]\s*)/
@@ -983,11 +1022,16 @@
  hi def link vimContinue	Special
  hi def link vimContinueComment	vimComment
  hi def link vimCtrlChar	SpecialChar
+ hi def link vimDefComment	vimComment
+ hi def link vimDefKey	vimCommand
+ hi def link vimDefParam vimVar
  hi def link vimEcho	vimCommand
  hi def link vimEchohlNone	vimGroup
  hi def link vimEchohl	vimCommand
  hi def link vimElseIfErr	Error
  hi def link vimElseif	vimCondHL
+ hi def link vimEndfunction	vimCommand
+ hi def link vimEnddef	vimCommand
  hi def link vimEnvvar	PreProc
  hi def link vimError	Error
  hi def link vimEscape	Special
@@ -998,8 +1042,13 @@
  hi def link vimFor	vimCommand
  hi def link vimFTCmd	vimCommand
  hi def link vimFTOption	vimSynType
+ hi def link vimFuncBang	vimBang
+ hi def link vimFuncComment	vimComment
  hi def link vimFuncKey	vimCommand
  hi def link vimFuncName	Function
+ hi def link vimFuncMod	Special
+ hi def link vimFuncParam	vimVar
+ hi def link vimFuncParamEquals	vimOper
  hi def link vimFuncSID	Special
  hi def link vimFuncVar	Identifier
  hi def link vimGroupAdd	vimSynOption